Periodic Trends Flashcards: Atomic Radius, Ionization Energy & Electronegativity
Review 88 concise cards on atomic and ionic radius, shielding, effective nuclear charge, ionization energy, electron affinity, electronegativity, metallic character, exceptions, and comparisons.
اس ڈیک کے بارے میں
Periodic Trends Flashcards: Atomic Radius, Ionization Energy & Electronegativity
Study the core periodic trends with 88 independently written English flashcards for high-school and introductory-college chemistry. The deck separates broad patterns from the reasons behind them and uses generally where real configurations create exceptions.
What the cards practice
The sequence covers four useful recall paths: term to definition; table movement to a general property direction; cause to effect through shell number, shielding, distance, and effective nuclear charge; and a concrete pair or isoelectronic set to the expected comparison. Atomic and ionic radius, first and successive ionization energies, electron affinity, electronegativity, metallic character, and selected reactivity links are all included.
The course-level exceptions are deliberately small: Be versus B, Mg versus Al, N versus O, P versus S, and Cl versus F electron affinity. Electron-affinity wording distinguishes a favorable electron gain from the sign convention used by a source. Electronegativity stays tied to bonded atoms, and ionic-radius comparisons state when an isoelectronic rule applies.
Learning order
Definitions and table structure come first. General directions follow, then causal models, ion-size rules, successive-ionization reasoning, limited exceptions, and applied comparisons. Related prompts are spaced apart in a fixed order; the review scheduler handles longer-term interleaving after installation.
Scope
This deck teaches qualitative periodic-trend reasoning. It excludes exact numerical property tables, memorizing values for all 118 elements, advanced transition-metal irregularities, diagonal relationships, melting and boiling trends, broad group trivia, and copied examination or competitor material. It supports chemistry practice but does not replace calculation, laboratory, or full-course problem solving.
Sources and license
Core trends and explanations were checked against OpenStax Chemistry: Atoms First 2e, section 3.5 and its electronegativity discussion in section 4.2. Terminology was cross-checked against the IUPAC Gold Book entries for ionization energy, electron affinity, and electronegativity.
The prompts, answers, examples, organization, metadata, and generated cover were created independently from common chemistry knowledge and original work. No protected cards, textbook prose, source figures, exact property tables, logos, or third-party media were copied.
The Common knowledge · CC0 1.0 label applies only to the original prompts, answers, examples, organization, metadata, and cover, to the extent applicable rights exist. It does not claim ownership of scientific facts or third-party material.
Source review date: August 29, 2026.
اس ڈیک کے کارڈز
کارڈ 1
سوال
What is a periodic trend?
جواب
A recurring pattern in element properties as atomic number increases across periods and down groups.
کارڈ 2
سوال
What does covalent radius measure?
جواب
Half the distance between the nuclei of two identical atoms joined by a covalent bond.
کارڈ 3
سوال
What is first ionization energy?
جواب
The minimum energy needed to remove the most loosely bound electron from an isolated gaseous atom in its ground state.
کارڈ 4
سوال
What is electronegativity?
جواب
An atom's ability to attract shared electrons toward itself in a chemical bond.
کارڈ 5
سوال
What is a period on the periodic table?
جواب
A horizontal row. For main-group elements, moving across a period fills orbitals in the same principal electron shell.
کارڈ 6
سوال
What is ionic radius?
جواب
A measure of an ion's size, usually inferred from distances between ions in crystals.
کارڈ 7
سوال
What does electron affinity describe?
جواب
The energy change when an electron is added to an isolated gaseous atom to form a gaseous anion.
کارڈ 8
سوال
What does metallic character describe?
جواب
How readily an element shows metallic behavior, especially losing valence electrons and forming cations.
کارڈ 9
سوال
What is a group on the periodic table?
جواب
A vertical column. Main-group elements in one group usually share a valence-electron pattern and similar chemistry.
کارڈ 10
سوال
What is effective nuclear charge?
جواب
The net positive pull an electron feels from the nucleus after shielding and electron–electron repulsion are taken into account.
کارڈ 11
سوال
What are successive ionization energies?
جواب
The energies needed to remove electrons one after another from the same atom, then from its increasingly positive ions.
کارڈ 12
سوال
How does electronegativity difference relate to bond polarity?
جواب
A larger difference generally produces a more uneven electron distribution and a more polar bond.
کارڈ 13
سوال
Why do main-group elements in one group often behave similarly?
جواب
They have the same general number and arrangement of valence electrons, which drive much of their bonding and reactivity.
کارڈ 14
سوال
What is electron shielding?
جواب
The reduction in nuclear attraction felt by an electron because other electrons lie between it and the nucleus and repel it.
کارڈ 15
سوال
Why does the definition of ionization energy specify a gaseous atom?
جواب
It isolates the atom from bonding and intermolecular effects, so the energy reflects electron removal from that species itself.
کارڈ 16
سوال
Where are metals and nonmetals generally found on the periodic table?
جواب
Metals occupy the left and center; nonmetals cluster toward the upper right, with metalloids near the boundary.
کارڈ 17
سوال
What changes in the electron arrangement across a main-group period?
جواب
Electrons are added to the same principal shell while the nucleus gains one proton from one element to the next.
کارڈ 18
سوال
How does atomic radius generally change from left to right across a period?
جواب
It decreases.
کارڈ 19
سوال
How does first ionization energy generally change from left to right across a period?
جواب
It increases, although a few recurring subshell and electron-pairing exceptions interrupt the rise.
کارڈ 20
سوال
How does electronegativity generally change from left to right across a period?
جواب
It increases for the elements normally assigned electronegativity values.
کارڈ 21
سوال
What changes in the electron arrangement down a main-group group?
جواب
Each step adds a higher principal electron shell while preserving a similar valence-electron pattern.
کارڈ 22
سوال
How does atomic radius generally change down a group?
جواب
It increases.
کارڈ 23
سوال
How does first ionization energy generally change down a group?
جواب
It decreases.
کارڈ 24
سوال
How does electronegativity generally change down a group?
جواب
It decreases.
کارڈ 25
سوال
How does effective nuclear charge generally change across a main-group period?
جواب
It increases because nuclear charge rises while added electrons enter the same principal shell and do not fully shield one another.
کارڈ 26
سوال
How does a cation's radius compare with its neutral parent atom?
جواب
The cation is smaller.
کارڈ 27
سوال
How does electron addition generally change across a period?
جواب
It generally becomes more energetically favorable toward the right, but electron affinity has substantial exceptions and depends on the sign convention used.
کارڈ 28
سوال
How does metallic character generally change from left to right across a period?
جواب
It decreases.
کارڈ 29
سوال
Why are valence electrons generally farther from the nucleus down a group?
جواب
They occupy shells with higher principal quantum numbers, so the electron cloud extends farther outward.
کارڈ 30
سوال
How does an anion's radius compare with its neutral parent atom?
جواب
The anion is larger.
کارڈ 31
سوال
How does favorable electron addition generally change down a group?
جواب
It generally becomes less favorable as the added electron enters a larger, more shielded shell, though electron-affinity irregularities are common.
کارڈ 32
سوال
How does metallic character generally change down a group?
جواب
It increases.
کارڈ 33
سوال
Why does shielding change less than nuclear charge across a main-group period?
جواب
The added electrons enter the same principal shell, so they do not shield one another as effectively as inner-shell electrons do.
کارڈ 34
سوال
Which has the larger atomic radius, Li or Na?
جواب
Na. It lies below Li and has an additional occupied electron shell.
کارڈ 35
سوال
Which has the larger atomic radius, Na or Mg?
جواب
Na. Atomic radius generally decreases from left to right across Period 3.
کارڈ 36
سوال
How does greater electron–nucleus distance affect electrostatic attraction?
جواب
It weakens the attraction, all else being equal.
کارڈ 37
سوال
How do successive ionization energies for one element compare?
جواب
Each successive ionization energy is higher than the one before it because an electron is removed from an increasingly positive species.
کارڈ 38
سوال
Which has the higher first ionization energy, Li or Na?
جواب
Li. Its valence electron is closer to the nucleus and less shielded.
کارڈ 39
سوال
Which has the higher first ionization energy, Na or Mg?
جواب
Mg. Its greater effective nuclear charge holds the valence electrons more tightly.
کارڈ 40
سوال
Why does forming a cation usually shrink an atom?
جواب
Electron loss reduces electron–electron repulsion and increases the nuclear pull per remaining electron; losing the outer shell can shrink it sharply.
کارڈ 41
سوال
Which element is most electronegative on the Pauling scale?
جواب
Fluorine.
کارڈ 42
سوال
Which is more electronegative, Li or Na?
جواب
Li. Electronegativity generally decreases down Group 1.
کارڈ 43
سوال
Which is more electronegative, Na or Mg?
جواب
Mg. Electronegativity generally increases across Period 3.
کارڈ 44
سوال
What does a large jump between successive ionization energies reveal?
جواب
The next electron would come from a lower, core shell; the number removed before the jump indicates the valence-electron count for a main-group atom.
کارڈ 45
سوال
Why is Cl⁻ larger than neutral Cl?
جواب
The added electron increases repulsion within the valence shell while the nuclear charge stays the same.
کارڈ 46
سوال
How do you compare the radii of isoelectronic species?
جواب
The species with more protons is smaller because the same number of electrons feels a stronger nuclear attraction.
کارڈ 47
سوال
Why does an atom have no single sharp physical radius?
جواب
Its electron cloud has no hard edge, so atomic size depends on a defined measurement such as covalent, metallic, or van der Waals radius.
کارڈ 48
سوال
Why are noble-gas electronegativities often omitted in introductory tables?
جواب
Electronegativity describes attraction in a bond, and many noble gases form too few ordinary bonds for a standard value to be useful on common scales.
کارڈ 49
سوال
Why does forming an anion usually expand an atom?
جواب
The extra electron increases electron–electron repulsion and lowers the nuclear pull available per electron.
کارڈ 50
سوال
Order O²⁻, F⁻, and Ne from largest to smallest radius.
جواب
O²⁻ > F⁻ > Ne. All have 10 electrons, and increasing proton count pulls that electron cloud inward.
کارڈ 51
سوال
After which removal does Na show its first large ionization-energy jump?
جواب
After the first electron. Removing one valence electron leaves a stable core, so the second removal reaches that core.
کارڈ 52
سوال
Does electronegativity difference create a universal ionic-versus-covalent cutoff?
جواب
No. A larger difference usually means more bond polarity, but bonding lies on a continuum and context matters.
کارڈ 53
سوال
How do noble gases generally differ from halogens in electron affinity?
جواب
Adding an electron to a noble gas is generally unfavorable because it must begin a higher-energy shell; halogens usually gain one much more favorably.
کارڈ 54
سوال
Which is smaller, Na⁺ or Mg²⁺?
جواب
Mg²⁺. Both have 10 electrons, but Mg²⁺ has one more proton.
کارڈ 55
سوال
After which removal does Mg show its first large ionization-energy jump?
جواب
After the second electron. Mg has two valence electrons, so the third removal reaches a core shell.
کارڈ 56
سوال
How does electronegativity differ from electron affinity?
جواب
Electronegativity is a relative measure of attraction for shared electrons in a bond; electron affinity is an energy change for adding an electron to an isolated gaseous species.
کارڈ 57
سوال
How are atomic radius and first ionization energy generally related?
جواب
A larger radius usually means a lower first ionization energy because the valence electron is farther from the nucleus and easier to remove.
کارڈ 58
سوال
Which has the more exothermic first electron affinity, F or Cl?
جواب
Cl. Fluorine's very compact 2p shell creates stronger electron–electron repulsion for the incoming electron, so this pair breaks the simple down-group expectation.
کارڈ 59
سوال
Which has the higher first ionization energy, Be or B?
جواب
Be. B loses a higher-energy 2p electron, while Be loses a more penetrating 2s electron from a filled 2s subshell.
کارڈ 60
سوال
Why does Group 1 metal reactivity generally increase down the group?
جواب
The valence electron is farther out and more shielded, so its first ionization energy falls and electron loss becomes easier.
کارڈ 61
سوال
How are atomic radius and electronegativity generally related?
جواب
Smaller atoms usually attract bonding electrons more strongly, so electronegativity tends to rise as radius falls.
کارڈ 62
سوال
Why is Na⁺ much smaller than neutral Na?
جواب
Na loses its entire third-shell valence level, leaving the smaller neon-like electron configuration.
کارڈ 63
سوال
Which has the higher first ionization energy, Mg or Al?
جواب
Mg. Al's removed electron is a higher-energy 3p electron, while Mg loses a more penetrating 3s electron from a filled 3s subshell.
کارڈ 64
سوال
Why does halogen reactivity generally decrease down Group 17?
جواب
Larger radius and greater shielding weaken attraction for an incoming electron, so oxidizing ability generally falls. Particular reactions still depend on bond energies and conditions.
کارڈ 65
سوال
Why do Groups 2 and 15 often interrupt the simple electron-affinity trend?
جواب
Group 2 has a filled s subshell and Group 15 has a half-filled p subshell, so an added electron enters a less favorable arrangement.
کارڈ 66
سوال
Can ion charge alone rank two unrelated ionic radii?
جواب
No. Shell number, electron count, proton count, oxidation state, and crystal environment can all matter; the isoelectronic rule needs the same electron count.
کارڈ 67
سوال
Which has the higher first ionization energy, N or O?
جواب
N. Its half-filled 2p subshell is relatively stable; O has one paired 2p orbital, and repulsion makes one electron easier to remove.
کارڈ 68
سوال
In which direction does nonmetallic character generally increase?
جواب
Up and to the right, opposite the general trend in metallic character.
کارڈ 69
سوال
Within the same principal shell, which penetrates closer to the nucleus: an s or p orbital?
جواب
An s orbital. Greater penetration means its electrons are less shielded and usually lower in energy than p electrons in the same shell.
کارڈ 70
سوال
How do same-charge ion radii generally change down a group?
جواب
They increase as occupied electron shells are added.
کارڈ 71
سوال
Which has the higher first ionization energy, P or S?
جواب
P. Its half-filled 3p subshell is relatively stable; S contains a paired 3p orbital that increases repulsion and eases removal.
کارڈ 72
سوال
Why should simple periodic-direction rules be used cautiously for transition metals?
جواب
d-electron filling, shielding, oxidation state, and contraction effects make their property changes less regular than main-group trends.
کارڈ 73
سوال
Why do periodic-trend statements usually say “generally”?
جواب
Subshell energies, electron pairing, radius definitions, and element-specific configurations create real exceptions to the broad patterns.
کارڈ 74
سوال
Which has the larger atomic radius, K or Br?
جواب
K. Both are in Period 4, and atomic radius generally decreases from left to right.
کارڈ 75
سوال
Which has the higher first ionization energy, Mg or Cl?
جواب
Cl. Its valence electrons experience greater effective nuclear charge and are held more tightly.
کارڈ 76
سوال
Which is more electronegative, Al or Si?
جواب
Si. Electronegativity generally increases across Period 3.
کارڈ 77
سوال
Which has the larger atomic radius, O or F?
جواب
O. Atomic radius generally decreases across Period 2.
کارڈ 78
سوال
Which has the higher first ionization energy, K or Br?
جواب
Br. First ionization energy generally increases across Period 4.
کارڈ 79
سوال
Which is more electronegative, Mg or Cl?
جواب
Cl. It lies farther right in Period 3.
کارڈ 80
سوال
Which has the larger atomic radius, Al or Si?
جواب
Al. Atomic radius generally decreases across Period 3 as effective nuclear charge rises.
کارڈ 81
سوال
Which has the higher first ionization energy, O or F?
جواب
F. This pair follows the general increase across Period 2.
کارڈ 82
سوال
Which is more electronegative, K or Br?
جواب
Br. Electronegativity generally increases across Period 4.
کارڈ 83
سوال
Which has the larger atomic radius, Mg or Cl?
جواب
Mg. Both are in Period 3, and Mg lies farther left.
کارڈ 84
سوال
Which has the higher first ionization energy, Al or Si?
جواب
Si. This pair follows the general increase across Period 3.
کارڈ 85
سوال
Which is more electronegative, O or F?
جواب
F, the most electronegative element on the Pauling scale.
کارڈ 86
سوال
Order Al³⁺, Mg²⁺, Na⁺, Ne, F⁻, and O²⁻ from smallest to largest radius.
جواب
Al³⁺ < Mg²⁺ < Na⁺ < Ne < F⁻ < O²⁻. All have 10 electrons, so radius grows as proton count falls.
کارڈ 87
سوال
Why do upper-right nonmetals usually hold valence electrons tightly?
جواب
Their relatively small radii and high effective nuclear charges create strong attraction between the nucleus and valence electrons.
کارڈ 88
سوال
Across a main-group period, what shared cause links smaller radius, higher ionization energy, and higher electronegativity?
جواب
Increasing effective nuclear charge pulls the same-shell valence electrons inward and holds them more strongly.
88 کارڈز
Periodic Trends Flashcards: Atomic Radius, Ionization Energy & Electronegativity
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